Bacterial artificial chromosomes (BACs) are large F-factor-based plasmids that serve as versatile tools for cloning and modification of large DNA sequences up to 300. kbp in Escherichia coli. BAC vectors allow the generation of whole genome libraries for the sequencing of eukaryotic genomes and the generation of transfer vectors that are important for the generation of transgenic animals. BACs can also be used to maintain toxic or instable sequences in bacteria and to clone and modify full-length virus genome sequences in Escherichia coli.
Kaufer, B. B., & Tischer, B. K. (2013). BACs (Bacterial Artificial Chromosomes). In Brenner’s Encyclopedia of Genetics: Second Edition (pp. 251–253). Elsevier Inc. https://doi.org/10.1016/B978-0-12-374984-0.00124-8